Automation Direct com error 2 with Direct Logic 205

Hello,

I am a Mfg. Eng. trying to figure why an Automation Direct HMI (DP-C321) has stopped communicating to a Direct Logic 205 PLC.

The machine has been running well for over 7 years. However, lately the HMI has been giving a "communication error on the RS232 port" . The error on the screen reads the value is 2. This error appears when the port is tested. The HMI is now not communicating at all with the PLC.

We checked continuity on the cable (DP-2CBL-A). And the (3) wires used have continuity.

I am not sure where to look from here.

Check 24 DC supply to HMI. Voltage and AC ripple.
Replace battery in HMI. It's a CR2025.
Check communication settings - not sure if it would "forget" settings with a bad battery.

Comm error

keithkyll,

Thanks for the response.

Will I lose the program if I change the battery?

The work on this machine is performed after hours (5 pm)

I will also check on the voltages to the panel.

I doubt it. I think the battery is for the clock and setup. I suspect the battery is already dead.
It should have a capacitor so you have several seconds to change battery.

keithkyll,

We changed the battery, but the issue remained. We checked voltage to the HMI, power supply was putting out 26 vdc. Unit is rated for 28.

Was not sure how to check AC ripple.

We investigate the DC power supply and noticed that we were getting continuity between the line voltage and the neutral on the primary side (110v) side of the power supply.

We are going to try another power supply tomorrow.

Do you think this is the right approach?

Thanks for all the help

PSU

keithkyll,

We changed the battery, but the issue remained. We checked voltage to the HMI, power supply was putting out 26 vdc. Unit is rated for 28.

Was not sure how to check AC ripple.

We investigate the DC power supply and noticed that we were getting continuity between the line voltage and the neutral on the primary side (110v) side of the power supply.

We are going to try another power supply tomorrow.

Do you think this is the right approach?

Thanks for all the help

PSU

Neutral is at ground potential. Negative side of supply output is probably grounded. Not an issue. Ripple is measured with an Oscilloscope. Poor man's way is to measure using Fluke in AC mode. Don't worry about that now. Supply is probably good.
Was battery bad? Check display setup parameters, mainly RS232 settings. Do you have manual? If not, here's the link from AD.

I disagree,
If you have the screen turning on, I highly doubt it's a power supply issue.
If its not comming on at all, then maybe it would be a power supply.

I would look into the rs232 connector and cable. Look for missing/broke pins or messed up comm cable from hmi to plc.

Has anyone messed with the programs or been connected before this issue?
If so:
1. Check plc comm settings.
2. Check HMI comm settings.


Could be a blown electrical component on the board, hopefully the is stored on a MC in the HMI.

keithkyll and Timeismoney08,

Thanks for the manual link.

You guys were right about the power supply.

The company has a similar machine on their floor with same HMI and PLC set-up. Checked the com setting on both machines by touching the screen in upper left and lower right. The setting are identical.

Can a cable be bad if their is continuity in the wires to the PLC? Also bent the pins slight to insure contact with HMI receiver. Still no communication to PLC.

I am familiar with GE Fanuc and have cables for some of their PLC's along with their software. However, I do not have experience with automation direct software and do not have their software.

I was hoping to avoid going into the operating system of the PLC or HMI but according to everyone's comments this sounds like the next step.

Running for 7 years, intermittent, now solid comms failure. Program didn't change. Hardware failed.
No software? Do you have software backups? If you need to replace the HMI or PLC CPU, you'll need software to download a copy of the program.

Can you try the HMI on the working machine? Extremely low risk of crashing other machine, but I wouldn't try it without backups.

Quick static test of RS232 ports. With cable unplugged, each unit will have -7 to -12 volts on either pin 2 or pin 3.

Use this tester to see which device is not transmitting.

Keithkyll,

Thanks for all the help, but my main job is sending me to Germany for a week. Plus I am a little timid to learn Automation Direct software when they have no back-ups. All programs are only in the PLC and HMI.

I gave the company a contact I use quite often that specializes in controls. The company is most likely going to back up all their systems and fix the issue.

If you want I can let you know what the problem is when they find it.

Thanks for all your help, I learned a lot during our conversations,

PSU

Yes, please post updates. Have fun in Germany.

Ok I will let you know when back in States